The present invention generally relates to catheters, and in particular, to a low profile catheter valve which may be opened to permit inflation or deflation of a catheter balloon, such as an occlusion balloon, and which may be closed when it is desirable to maintain the catheter balloon in an inflated state.
Guidewires are conventionally used to guide the insertion of various medical instruments, such as catheters, to a desired treatment location within a patient""s vasculature. In a typical procedure, the clinician forms an access point for the guidewire by creating an opening in a peripheral blood vessel, such as the femoral artery. The highly flexible guidewire is then introduced through the opening into the peripheral blood vessel, and is then advanced by the clinician through the patient""s blood vessels until the guidewire extends across the vessel segment to be treated. Various treatment catheters, such as a balloon dilatation catheter for a percutaneous transluminal coronary angioplasty, may then be inserted over the guidewire and similarly advanced through vasculature until they reach the treatment site.
In certain treatment procedures, it is desirable to successively introduce and then remove a number of different treatment catheters over a guidewire that has been placed in a particular location. In other words, one treatment catheter is xe2x80x9cexchangedxe2x80x9d for another over a single guidewire. Such an exchange typically involves withdrawing the treatment catheter over the guidewire until the treatment catheter is fully removed from the patient and the portion of the guidewire which extends from the patient. The guidewire is then available to act as a guide for a different treatment catheter.
In emboli containment devices, which typically utilize two occlusion balloons to form a chamber, it may be desirable to exchange therapeutic catheters without deflating the occlusion balloons. Further, it is sometimes advantageous to anchor the guidewire during the exchange. As can be readily appreciated, the withdrawal of treatment catheters over a placed guidewire may result in the guidewire being displaced from its position. To overcome this difficulty, the prior art has developed xe2x80x9canchorablexe2x80x9d guidewires, which generally feature some structure on their distal ends to releasably secure the guidewire at a particular location in the patient for the duration of the medical procedure. One such anchorable guidewire is disclosed in U.S. Pat. No. 5,167,239 to Cohen et al., which discloses a hollow guidewire with an inflation lumen and an expandable balloon on its end. The Cohen guidewire is positioned in the same manner as a conventional wire guidewire, but once placed, its expandable balloon is inflated to contact the surrounding vasculature, thereby preventing the guidewire from being displaced.
Because a permanent inflation manifold, of the type used with conventional catheters having an inflatable balloon, would prevent other catheters from being inserted over the Cohen guidewire, the Cohen device also includes a removable inflation manifold, and a check valve to maintain the balloon in the inflated state when the manifold is removed. The check valve apparatus used by the Cohen device is relatively bulky, and is described as having an outer diameter in its preferred embodiment of 0.0355 inches. Consequently, any treatment catheter intended to be inserted over the Cohen device must have an interior guidewire lumen larger than the outer diameter of the Cohen valve, which for the preferred embodiment, requires an interior lumen with a diameter of more than 0.0355 inches.
As is readily appreciated by those of skill in the art, increasing the interior lumen size of a treatment catheter results in an increase in the outer diameter of the treatment catheter. For treatment procedures which take place in vasculature having a large blood vessel diameter, such as iliac arteries, a treatment catheter guidewire lumen of a size necessary to accommodate devices such as those described by Cohen would have little or no affect on the ability of the catheter to fit within the blood vessel. However, many blood vessels where it is desirable to apply catheter treatment are quite narrow. For example, the left coronary arteries are blood vessels having diameters ranging from 2 to 4 mm, and are susceptible to plaque. It would be desirable to use a catheter exchange treatment procedure, such as angioplasty, to treat such lesions, but the narrow diameter of the coronary vessels makes use of anchorable guidewires having large valve diameters impractical.
Consequently, there exists a need for a very low profile catheter valve which can be used with a hollow guidewire.
The present invention provides a catheter valve which is capable of very low profiles, and is especially advantageous for use with anchorable guidewires, as well as therapeutic or occlusion devices. By incorporating the valve of the present invention into such devices, it is possible to manufacture anchorable guidewires and occlusion device catheters with outer diameters of 0.014 inches or smaller. Advantageously, by utilizing the present invention in these cathetersi. clinicians will be able to use anchorable guidewires, therapeutic or occlusion device catheters in much narrower blood vessels than in the past.
In one aspect of the present invention, there is provided a valve which comprises a flexible elongate tubular body having a proximal end and a distal end. The tubular body has a central lumen extending between the proximal and distal ends. The central lumen has an opening at the proximal end.
An expandable member, such as an inflatable balloon, is positioned on the distal end of the tubular body. The expandable member is in fluid communication with the central lumen. An access opening is provided on the tubular body. The access opening is in fluid communication with the central lumen to permit the expandable member to be actuated by pressurizing the access opening.
A sealing member is provided having a sealer portion which seals against a surface of the tubular body. The sealing portion of the sealing member is movable relative to said surface of the tubular body between two positions. In the first position, the sealer portion is positioned in contact with the tubular body surface at a location which blocks the flow of fluid to or from the expandable member through the access opening to maintain actuation of the expandable member. In the second position, the sealer portion is positioned at a location which permits the flow of fluid to or from the expandable member through the access opening to permit actuation or deactuation of the expandable member.
In one preferred embodiment, the sealing member has a portion which extends from the proximal end of the tubular body, and the application of a longitudinal force on the extending portion results in movement of the sealer portion in the direction of the applied force. In other embodiments, rotational forces may be used to move the sealing member.
The sealer portion is preferably formed of a polymeric material, such as a thermoplastic elastomer resin such as PEBAX(trademark), C-FLEX(trademark), silicone, or gels. The sealer portion should be capable of withstanding balloon inflation pressures and prevent substantially all fluid from passing to or from the expandable member through the access opening when the sealer portion is positioned distal to the access opening. Advantageously, the outer diameter of the tubular body is generally larger than the outer diameter of any portion of the sealing member or sealer portion. In some embodiments, the outer diameter of the tubular body is no greater than 0.038 inches, preferably no greater than 0.020 inches, and more preferably no greater than 0.014 inches. Other embodiments may have larger outer diameters for the tubular body. The tubular body may also have positive stops to prevent withdrawal of the sealing member from the opening.
In another aspect of the present invention, there is provided an apparatus, comprising a hollow metallic guidewire having a central lumen and a side-access port in fluid communication with the lumen. An inflatable balloon is mounted on the guidewire, the inflatable balloon being in fluid communication with the central lumen, such that fluid introduced through the side-access port can be used to inflate the balloon.
A valve is mounted to slide along a surface of the guidewire, the valve movable between first and second positions, one of the positions sealing the central lumen such that substantially no fluid may pass to or from theand inflatable balloon by way of the side-access port.
Preferably, the hollow guidewire has an outer circumference defining a first value, and wherein the movable valve has a circumference which is less than the first value. It is also preferred that the hollow guidewire have an outer circumference of 0.12 inches or less, more preferably 0.08 inches or less, and optimally 0.044 inches or less, and that the movable valve have a diameter not substantially larger than that of the hollow guidewire.
In another aspect of the present invention there is provided a low profile catheter valve which comprises a sealing member capable of being movably inserted through a proximal opening on a catheter into an inflation lumen of the catheter. The catheter has a side-access inflation port and an inflatable balloon in fluid communication with the side-access inflation port. A sealer portion is on the sealing member, the sealer portion being capable of forming a fluid tight seal with the entire circumference of a section of the lumen, such that substantially all fluid may not pass the sealer portion at normal balloon inflation pressures.
When the sealer portion is positioned within the lumen proximally of the side-access inflation port, an unrestricted fluid pathway is established between the side-access inflation port and the balloon. When the sealer portion is positioned within the lumen distally of the side-access inflation port, substantially all fluid may not pass to or from the balloon through the side-access inflation port at normal balloon inflation pressures.
In another aspect of the present invention, there is provided a method of inflating a catheter balloon. The first step of the method involves providing a tube having a proximal end and a distal end. The proximal end of the tube has an inflation opening to an inflation lumen and the distal end has an inflatable balloon in fluid communication with the inflation lumen. A pressurized inflation fluid is then introduced through the inflation opening to inflate the balloon. The inflation opening may then be sealed by moving a sealing member within the inflation lumen without reducing the pressure of the pressurized fluid, wherein the step of sealing is performed without substantial deflation of the inflated balloon. Finally, the pressure of the pressurized fluid may be reduced after completing the sealing step.
In another aspect of the present invention, there is provided a low profile catheter valve for use with an inflation adaptor. The valve comprises a sealing member capable of being movably inserted through a proximal opening on a catheter into an inflation lumen of the catheter. The catheter has an inflation opening and an inflatable balloon in fluid communication with the inflation opening. Indicia are present on the catheter and/or sealing member, the position of the indicia being such that the inflation opening is aligned with a fluid tight inflation chamber of the inflation adaptor when the catheter and sealing member are secured in the inflation adaptor.
A sealer portion is mounted on the sealing member. The sealer portion is capable of forming a fluid tight seal with the entire circumference of a section of the lumen, such that substantially all fluid may not pass the sealer portion at normal balloon inflation pressures. When the sealer portion is positioned proximally of the inflation opening, an unrestricted fluid pathway is established between the inflation opening and the balloon. When the sealer, portion is positioned distally of the inflation opening, substantially all fluid may not pass to or from the balloon through the sideaccess inflation port.
In another aspect of the present invention, there is provided an inflation adaptor for introducing inflation fluid into an inflation port of an elongate tube. The inflation adaptor comprises a housing having first and second portions which interact to releasably retain a section of the tube therein. The housing has a chamber which receives the inflation port. An inflation inlet configured to be connected to a source of inflation fluid that supplies said fluid under pressure is positioned on the housing.
A seal which releasably seals the portions of said housing together provides a fluid pathway between the inflation inlet and the inflation port, so that fluid may be supplied to the inflation port under pressure. An actuator, mounted on said housing, drives a member within the tube to control fluid flow through said inflation port.
In another aspect of the present invention, there is provided an inflation adaptor for introducing inflation fluid into an inflation port of an elongate tube. The inflation adaptor comprises a housing having first and second portions. The two portions form a mouth for receiving a section of the tube which includes the inflation port. The mouth forms an opening having a height at least as great as the outer diameter of the tube such that the section of tube is insertable into the mouth from its side in a direction transverse to the longitudinal axis of the tube. The housing also has an inflation chamber and an inflation inlet for introducing inflation fluid under pressure into the inflation chamber. The inflation chamber releasably seals the inflation port to the inflation inlet to form a fluid passage there between.
In another aspect of the present invention, there is provided an inflation adaptor for introducing inflation fluid into an inflation port of an elongate tube. The tube has an inflatable member mounted thereon and an inflation lumen between the inflation port and the inflatable member. The adaptor has a housing configured to seal over the tubular body to create a fluid tight seal. An inflation inlet is on the housing, for establishing a fluid pathway between the inflation inlet and the inflation port to permit the inflatable member to be inflated. The housing is detachable from the tube without deflating the inflated inflatable member.